Title of Invention

FUEL INJECTION CONTROL DEVICE FOR SINGLE-CYLINDER ENGINE

Abstract

To provide a fuel injection control device for a single-cylinder engine which can exhibit good startability not so inferior to the startability of a multicylinder engine and can be produced at a low cost. A pulse generator 2 generates a given number of pulse signals including a plurality of equally spaced crank angle pulses and unequally spaced crank angle pulses per rotation of a crankshaft of an engine. An ECU 3 performs initial fuel injection according to the pulse signals within the given number of pulse signals per rotation of the crankshaft, and sets injection control temporary stages and injection control permanent stages according to the pulse signals. The ECU 3 outputs commands of second and subsequent fuel injection and ignition to an injector 4 and a spark plug 5, respectively, according to the injection control temporary stages and the injection control permanent stages.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] FUEL INJECTION CONTROL DEVICE FOR SINGLE-CYLINDER ENGINE HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- [DETAILED DESCRIPTION OF THE INVENTION] [Technical Field to Which the Invention Pertains] The present invention relates to a fuel injection control device for a single-cylinder engine, and more t particularly to a fuel injection control device for a four-cycle single - cylinder engine improved in startability. [Prior Art] A fuel injection control method for improving the startability of a four-cycle multicylinder engine, e.g., a four-cycle four-cylinder, engine has conventionally been proposed as described in Japanese Patent Publication No., Sho 63-14174, for example. {0003] In general, a four-cycle four - cylinder engine has a crank angle sensor as an engine rotation sensor for indicating that the rotational position of a crankshaft has passed a specific crank angle during two rotations (a crank angle of 720") of the crankshaft, and a timing sensor for outputting a fuel injection start timing. According to the fuel injection control method described in the above publication, which is shown in FIG. 9, only at an initial fuel injection timing (time tl) immediately after starting of the engine (time tO), a necessary and sufficient amount of fuel is simultaneously injected from all of #1 to #4 injectors into the four cylinders, respectively. Subsequently, when the crankshaft is rotated 720", i.e., when ignition and explosion are finished once in each cylinder (time t2), the sequence of fuel injection to the four cylinders is shifted to a normal sequence. According to this method, fuel injection is carried out even at a timing immediately after starting of the engine in which the injector to be first operated cannot be specified, so that the startability is improved. In recent years, the need for adoption of fuel injection has increased also in a motorcycle, and fuel injection has already started to-he.adopted in a motorcycle having a multicylinder engine. On the other hand, a practical motorcycle of small displacement employs a single-cylinder engine in many cases, and the single-cylinder engine includes a four-cycle engine in many cases. In these circumstances, it is considered that fuel injection will be adopted also in a four-cycle single-cylinder engine in the future. However, if the above-mentioned fuel injection control at engine starting is applied to the four-cycle single-cylinder engine, the following problems occur. [ 0 0 0 C ] [Problem to be Solved by the Invention] (1) In a multicylinder engine such as a four-cylinder engine, there are two cylinders A and B whose phases are shifted from each other by one rotation (360") of a crankshaft. Accordingly, although control stages respectively corresponding to pulse durations obtained by dividing one rotation of the crankshaft are allocated to the cylinder A especially near the start of cranking (near the start of operation of a control system), but actually shifted by one rotation (360.) of the crankshaft, complete explosion can be performed in the cylinder B by injecting fuel into the cylinders A and B in a similar manner. As a result, there is no possibility of reduction in startability. Further, the cylinder B can be distinguished from the cylinder A by an output from the crank angle sensor within several rotations of the crankshaft after starting of the explosion. Accordingly, it is not necessary to shift the allocation of the control stages with respect to the crank angle, but it is only necessary to re-recognize that the control stages are actually allocated to the cylinder B rather than the cylinder A. However, in a single-cylinder engine, the cylinder B does not exist. Accordingly, if the control stages are snitted by one rotation (360) ot tne crankshaft from an actual crank angle, it is difficult to stably continue the explosion. As a result, the startability of the single-cylinder enqine is inferior to that of a multicylinder engine. Furthermore, when the shift of allocation of the control stages is detected, it is necessary to quickly correct the whole stages previously allocated. (2) A single-cylinder engine is inexpensive owing to its simple configuration, which is an important factor to attract. However, if the single-cylinder engine is provided with a crank angle sensor and a timing sensor similar to those in the multicylinder engine as mentioned aoove, a cose increase race due to the introduction of a fuel injection system into the single - cylinder engine becomes higher than that in the multicylinder engine, so that the attractive factor inherent to the single-cylinder engine is impaired. It is accordingly an object of the present invention to provide a fuel injection control device for a single-cylinder engine which can exhibit good startability not so inferior to the startability of a multicylinder engine and can be produced at a low cost. [Means of Solving the Problem] According to the present invention, there is provided a fuel injection control device for a single-cylinder engine, comprising pulse generating means for generating a given number of pulse signals including a plurality of equally spaced crank angle pulses and unequally spaced crank angle pulses per rotation of a crankshaft of the engine; injection control temporary stages allocated respectively to the durations of the pulse signals generated by the pulse generating means from the start of cranking; intake pressure measuring means for measuring an intake pressure of the engine a plurality of times during two rotations of the crankshaft according to the injection control temporary stages; and injection control permanent stages shifted from the injection control temporary stages according to measured values of the intake pressure obtained by the intake pressure measuring means; wherein initial fuel injection is performed within the given number of the pulse signals generated from the start of cranking per rotation of the crankshaft, and second and subsequent fuel injection and ignition are performed according to the injection control temporary stages and the injection control permanent stages. With this configuration, normal control can be reached by three revolutions of the crankshaft. Accordingly, it is possible to provide good startability not so inferior to the startability of a multicylinder engine. Furthermore, the fuel injection control device can be configured at a low cost, because it is not necessary to provide a cam pulser included in a multicylinder engine Accordingly, there is provided a fuel injection control device for a single-cylinder engine (22), characterized in that: pulse generating device having a pulse generator (2) and partially uhtoothed gear (1) for generating pulse signals having a plurality of equally spaced crank angle pulses and unequally spaced crank angle pulses per rotation of a crankshaft of said engine (22); injection control temporary stages allocated respectively to the durations of said pulse signals generated by said pulse generating device from the start of cranking; intake pressure measuring device (6) for measuring an intake pressure of said engine (22) two times in a constant intervals during two rotations of said crankshaft according to said injection control temporary stages; and injection control permanent stages shifted from said injection control temporary stages comparing a pair of the measured values of said intake pressure obtained by said intake pressure measuring device (6); wherein initial fuel injection" is performed within a rotation of said crankshaft from the start of cranking, and second and subsequent fuel injection and ignition are performed according to said injection control temporary stages and said injection control permanent stages. [BRIEF DESCRIPTION OF THE DRAWINGS] [FIG. 1] FIG. 1 is a block diagram showing the configuration of an essential part of the present invention. [FIG. 2] FIG. 2 is a flowchart illustrating the operation of a preferred embodiment of the present invention. [FIG. 3] FIG. 3 is a flowchart following the flowchart shown in FIG. 2. [FIG. 4] FIG. 4 is a timing chart showing the operation in the case of starting a four-cycle single-cylinder engine before a top dead center in a compression stroke in the preferred embodiment. [FIG. 5] FIG. 5 is a timing chart showing the operation in the case of starting the engine before a top dead center in an exhaust or intake stroke in the preferred embodiment. [FIG. 6] FIG. 6 is a timing chart showing the operation in the case of starting the engine in the middle of an expansion stroke at a piston position corresponding to an untoothed position in the preferred embodiment. [FIG. 7] FIG. 7 is a side view of a motorcycle to which the present invention is applied. [FIG. 8] FIG. 8 is a partially sectional, side view showing the configuration of an engine and its peripheral portion of the motorcycle shown in FIG. 7. [FIG. 9] FIG. 9 is a timing chart for illustrating the operation of a four-cycle four-cylinder engine. [Preferred Embodiment] The present invention will now be described in detail with reference to the drawings. FIG. 7 is a side view showing a right-side external appearance of a motorcycle 10 on which the fuel injection control device of the present invention is mounted. As shown in FIG. 7, the motorcycle 10 includes a main frame 41 forming a vehicle body and a leg shield 13 covering the main frame 41 and extending so as to correspond to the legs of a rider. [0013] A handle stem 15 is rotatably supported to the front end of the main frame 41, and a front fork 16 is fixed to the lower end of the handle stem 15. A front is supported through an axle 23 to the lower he front fork 16. A front fender 18 is provided front wheel 17. A rear body 14 is located behind the main frame 41, and a seat 19 is provided on the rear body 14. A pivot shaft 25 is provided at the lower end of the rear body 14, and a swing arm 20 is supported to the pivot shaft 25. The swing arm 20 is provided with a rear cushion 21. A four-cycle single-cylinder engine 22 is located at a central portion of the vehicle body. The configuration of the engine 22 and its peripheral portion will now be described with reference to FIG. 8. As shown in FIG. 8, a throttle valve 32 whose opening is controlled by a wire 33 and a throttle opening sensor are located downstream of an air cleaner 31 in respect of an air flow. An injector 35 for injecting a fuel into an intake pipe 34 to generate a fuel-air mixture is located downstream of the throttle valve 32. The injector 35 is directed so that the fuel-air mixture is sprayed toward an inlet valve 36 of the engine 22. In this preferred embodiment, the engine 22 is a four-cycle single-cylinder engine, and it includes a spark plug 37, an exhaust port 38, and an engine oil temperature sensor 39. Reference numeral 40 denotes a crankcase for accommodating a crankshaft connected to a piston. The crankcase 40 is supported to a bracket 42 and a pivot bracket 43 both fixed to the main frame 41. The crankcase 40 is provided with a partially untoothed reluctor 46 and a crank pulser 47. A self - starting motor 45 is located near the crankcase 40. The configuration of an essential part of the preferred embodiment of the present invention will now be described with reference to FIG. 1. As shown in FIG. 1, this preferred embodiment consists essentially of a partially untoothed gear 1 adapted to be rotated 360" by one rotation of a crankshaft and having equally spaced nine teeth and an untoothed portion, a pulse generator 2 for generating nine pulses including an untoothed pulse per rotation of the gear 1, an ECU (electronic control unit) 3 for controlling the starting of a four-cycle single-cylinder engine according to pulse signals generated from the pulse generator 2, an injector 4 (35) whose fuel injection timing and fuel injection amount are controlled by the ECU 3, a spark plug 5 (37) whose ignition timing in a combustion chamber is controlled by the ECU 3, and an intake pressure sensor 6 for detecting an air pressure in an intake pipe. The start control function of the ECU 3 in this preferred embodiment will now be described with reference to FIGS. 2 to 6. FIGS. 2 and 3 are flowcharts showing the start control function, FIG. 4 is a timing chart showing the operation in the case of starting the four-cycle single-cylinder engine before a top dead center in a compression stroke, FIG. 5 is a timing chart showing the operation in the case of starting the engine before a top dead center in an exhaust or intake stroke, and FIG. 6 is a timing chart showing the operation in the case of starting the engine in the middle of an expansion stroke. [Q018] The operation in the case of starting the engine before a top dead center in a compression stroke will now be described with reference to FIGS. 2, 3, and 4. When the engine is started at a time to shown in FIG. 4, the processing of steps SI to S3 shown in FIG. 2 is started, that is, the number n of pulses from the partially untoothed gear 1 starts to be counted by the ECU 3. When the number n of pulses counted in step S2 becomes 3, for example, the program proceeds to step S14, in which the ECU 3 outputs a command of injecting a given minute amount of fuel to the injector 4. This corresponds to initial fuel injection at a time tl shown in FIG. 4. The number n of pulses effecting the initial fuel injection is not limited to 3, but it is sufficient to satisfy the condition of (the number of pulses effecting the initial fuel injection) = (the number of pulses per rotation of the crankshaft)/2. The reason for this condition is that if the timing of the initial fuel injection is too late in the case that the engine is standing still in the middle of an exhaust stroke, a fuel-air mixture cannot be taken into the combustion chamber in an intake stroke falling within a crank angle of 180" from a cranking start time, so that the effect of improving the startability may be reduced. Further, the injection duration, or injection amount for the initial fuel injection may be determined according to temperatures of the engine. As apparent from FIG. 4, the pulse (e.g., Mel or MelO) immediately preceding an untoothed pulse as taken in the rotating direction of the partially untoothed gear 1 corresponds to a top dead center (TDC) of the piston. When the decision in step S3 becomes affirmative, that is, when the gear 1 is rotated 360*, the ECU 3 performs the processing of step S4 to detect an untoothed position (= N) . That is, when the condition of Me(n) -Me(n + 1) > {Me(n + 1) - Me(n +2)} x S (where S is an arbitrary number satisfying 1 compression stroke or in an exhaust stroke. To detect this, the following processing is performed. {0020] In step S5, the ECU 3 decides a temporary stage No. (= m) by using the above untoothed position N. The temporary stage No. (= m) is decided as m = (15 - N). In the case shown in FIG. 4, N = 2 and therefore m = 13. Subsequently, the decisions in steps S6 to Sll are made. That is, it is determined whether or not the temporary stage No. m is equal to any one of 3, 4, 10, 12, 13, and 18. It is predetermined that when the temporary stage No. m becomes any one of the above numbers, given processing to be hereinafter described is performed. As shown in FIG. 4, the temporary stage No. m at starting is 13. Accordingly, the decision in step S10 becomes affirmative and the program proceeds to step S12, in which it is determined whether or not intake pressures Pbl and Pb2 have been read,. If the decision in step S12 is negative, the program proceeds to step S13, in which fuel injection is performed in an amount determined according to a throttle opening and an engine speed Ne. The reason for this flow is that it is predetermined that when the temporary stage No. m is 13, fuel injection is performed. Subsequently, the program proceeds to step Sll. In step Sll, it is determined whether or not the temporary stage No. m is 18. If the decision in step Sll is negative, the program proceeds to step S15, in which the temporary stage No. m is incremented by 1, and the program returns to step S6 shown in FIG. 2. The processing of steps S6 to Sll and S15 is repeated to increment the temporary stage No. m one by one until the temporary stage No. m becomes 18. When the decision in step Sll becomes affirmative, the program, proceeds to step S16, in which the temporary stage No. m is reset to 0. Then, the program proceeds to step S17, in which the first intake pressure Pbl is read. It is assumed that a minimum value of the intake pressure Pb is held until the reading of the first intake pressure Pbl is ended. It is apparent that the timing at which the intake pressure Pb has become the minimum value corresponds to an intake stroke of the engine. Subsequently, the program proceeds to step S15, in which the temporary stage No. m is incremented by 1. The processing of steps S6 to Sll and S15 is repeated again until the decision in step S6 becomes affirmative. That is, when the temporary stage No. m becomes 3, the program proceeds to step S18, in which a command of first ignition is output to the spark plug 5. At this time, the fuel has already been supplied into the combustion chamber to fill the same, so that complete explosion occurs. Subsequently, when the decision in step S7 becomes affirmative (m = 4), the program proceeds to step S19, in which it is determined whether or not the intake pressures Pbl and Pb2 have been read. At this time, the decision in step S19 is negative because the intake pressure Pb2 has not yet been read. Subsequently, when the decision in step S8 becomes affirmative (m = 10), the program proceeds to step S20, in which the second intake pressure Pb2 is read. Subsequently, when the decision in step S9 becomes affirmative (m = 12), the program proceeds to step S21, in which a command of second ignition is output to the spark plug 5. At this time, however, no explosion occurs because the engine is in an exhaust stroke and no fuel is therefore present in the combustion chamber. Subsequently, when the decision in step S10 becomes affirmative (m = 13), the program proceeds to step S12, in which it is determined whether or not the first and second intake pressures Pbl and Pb2 have been read. If the decision in step S12 becomes affirmative, the program proceeds to step S22, in which it is determined whether or not the condition of Pbl > Pb2 holds. In the present case shown in FIG. 4, the decision in step S22 is negative. Accordingly, the program proceeds to step S23, in which the temporary stage No. m = 13 is decided as a permanent stage No. 13, because the decision in step S22 has made it clear that the top dead center (TDC) in the temporary stage No. m = 13 is the top dead center in the exhaust stroke. 40027,] In step S25, fuel injection is performed in an amount determined according to an engine speed Ne and other parameters. Subsequently, the program proceeds to step S26, in which the processing of the permanent stages is performed. That is, fuel injection is performed in a duration and amount read from a MAP according to stage computation. This fuel injection is performed normally during stage Nos. 4 to 11. This is due to the fact that a small-displacement motorcycle engine is operated at high speeds and it is therefore necessary to start fuel injection at an early timing. Furthermore, in step S26, ignition is performed at a timing read from a MAP according to stage computation. This ignition is performed normally during stage Nos. 1 to 3. ^0020] Thus, in the case of FIG. 4, at the time the crankshaft is rotated by two revolutions (720*) from starting of the engine, the fuel is completely exploded and normal operation is started. Accordingly, startability no so inferior to that of a multicylinder engine can be provided. The operation in the case of starting the engine before a top dead center in an exhaust or intake stroke will now be described with reference to FIGS. 2, 3, and This case is different from the case of FIG. 4 in that the phase is shifted 360". •[0030] The processing of steps SI to S5 shown in FIG. 2 similar to that in the case of FIG. 4. In step S5, the temporary stage No. m is decided as m = 13 like that in the case of FIG. 4. Since the temporary stage No. m is the decision in step S10 becomes affirmative, and the program proceeds to step S12 . The decision in step S12 negative, so that the fuel injection in step S13 is performed. At this time, the piston takes a top dead center (TDC) in a compression stroke, so that no fuel is supplied into the combustion chamber. Subsequently, the decision in step Sll becomes affirmative and the processing of step S17 is performed, i.e., the first intake pressure Pbl is read. At this time, the piston has not yet reached an intake stroke., so that the intake pressure Pbl indicates a value almost equal to an atmospheric pressure. Although the piston reaches an intake stroke immediately after starting of the engine, the intake pressure Pb is not lowered because the engine speed at this time has not yet been increased. [0031] Subsequently, the decision in step S6 becomes affirmative, and the ignition in step S18 is performed. However, no fuel is present in the combustion chamber at this time, so that no explosion is caused by the above ignition. Subsequently, the decision in step S7 becomes affirmative, and the program proceeds to step S19. At this time, the second intake pressure Pb2 has not yet been read, so that the decision in step S19 is negative. When the decision in step S8 becomes affirmative, the program proceeds to step S20, in which the second intake pressure Pb2 is read. A value of the intake pressure Pb in the intake stroke, i.e., a minimum value of the intake pressure Pb is held and the second intake pressure Pb2 is therefore lower than Pbl. When the decision in step S9 becomes affirmative, the program proceeds to step S21, in which a command of ignition is output. At this time, the fuel previously injected at the time t2 has already been supplied into the combustion chamber in the intake stroke after the temporary stage No. m = 4. Accordingly, the fuel is completely exploded by the ignition in step S21. That is, normal operation is started at this time. [0032] Subsequently, when the decision in step S10 becomes affirmative, the program proceeds, to step S12, in which it is determined whether or not the first and second intake pressures Pbl and Pb2 have been read. If this decision is affirmative, the program proceeds to step S22, in which it is determined whether or not the condition of Pbl > Pb2 holds. In the case of FIG. 5, this decision becomes affirmative. Then, the program proceeds to step S24, in which the temporary stage No. m = 13 is decided as a permanent stage No. 4, because the decision in step S22 has made it clear that the top dead center (TDC) in the temporary stage No. m = 13 is the top dead center in the compression stroke. Subsequently, the program proceeds to step S26, in which the process of the permanent stages is performed as similarly to the case of FIG. 4. That is, fuel injection is performed in a duration and amount read from a MAP according to stage computation. This fuel injection is performed normally during stage Nos. 4 to 11. This is due to the fact that a small-displacement motorcycle engine is operated at high speeds and it is therefore necessary to start fuel injection at an early timing. Furthermore, in step S26, ignition is performed at a timing read from a MAP according to stage computation. This ignition is performed normally during stage Nos. 1 to 3. E403A-] Thus, in the case of FIG. 5, normal operation is started at the timing of ignition in the temporary stage No. m = 12 . That is, at the time the crankshaft is rotated by three revolutions (720* + 360") from starting of the engine, the fuel is. completely exploded and normal operation is started. The operation in the case of starting the engine in the middle of an expansion stroke, i.e., in the case that the piston has been stopped at the untoothed position in the middle of an expansion stroke will now be described with reference to FIGS. 2, 3, and 6. In general, when the engine in a motorcycle or the like is stopped, the piston continues to move by inertia, and the friction to the crankshaft becomes largest in a compression stroke. Accordingly, there is a high probability that the piston may be stopped in an expansion stroke and the engine may be next started in the middle of the expansion stroke. Assuming that the engine is started at a time tO shown in FIG. 6, the processing of steps SI to S3 shown in FIG. 2 is performed as similarly to the case of FIG. 4. When the number n of pulses counted in step S2 becomes 3, for example, the program proceeds to step S14, in which the ECU 3 outputs a command of injecting a given minute amount of fuel to the injector 4. As a result, the given minute amount of fuel is injected at a time tl. When the decision in step S3 becomes affirmative and the program proceeds to step S4, the untoothed position N is detected to be 9. Accordingly, the temporary stage No. m is decided-as 6 in step S5, so that the temporary stages are started at No. 6. As a result, when the decision in step S8 becomes affirmative (m = 10), the program proceeds to step S20, in which the first intake pressure Pbl is read. At this time, the first intake pressure Pbl is a small value held in an intake stroke. Subsequently, when the decision in step S9 becomes affirmative (m = 12), the program proceeds to step S21, in which a command of ignition is output. At this time, the fuel previously injected at the time tl has already been supplied into the combustion chamber in the subsequent intake stroke, so that the fuel in the combustion chamber is completely exploded to start the engine. Subsequently, when the temporary stage No. m is incremented by 1 to result in m = 13, and the decision in step S10 becomes affirmative, the program proceeds to step S12, in which it it determined whether or not the first and second intake pressures Pbl and Pb2 have been read. At this time, the second intake pressure Pb2 has not yet been read, so that, the program proceeds to step S13, in which fuel is injected in an amount determined according to an engine speed Ne. When the temporary stage No. m is incremented one by one and the decision in step Sll becomes affirmative (m = 18), the program proceeds to step S16, in which the temporary stage No. m is reset to 0. Subsequently, the program proceeds to step S17, in which the second intake pressure Pb2 is read. It is apparent that the second intake pressure Pb2 is almost equal to an atmospheric pressure higher than the first intake pressure Pbl. Subsequently, when the decision in step S6 becomes affirmative (m = 3), the program proceeds to step S18, in which ignition is performed. However, since no fuel is present in the combustion chamber, no explosion occurs. Subsequently, when the decision in step S7 becomes affirmative (m = 4), the program proceeds to step S19, in which it is determined whether or not the first and second intake pressures Pbl and Pb2 have been read. Since the decision in step S19 is affirmative at this time, the program proceeds to step S27, in which it is determined whether or not the condition of Pbl > Pb2 holds. Since the decision in step S27 is negative in this case, the program proceeds to step S28, in which the temporary stage No. m = 4 is decided as a permanent stage No. 13, because the decision in step S27 has made it clear that the top dead center (TDC) in the temporary stage No. m = 4 is the top dead center in the exhaust stroke. Conversely, if the decision in step S27 is affirmative, the program proceeds to step S29, in which the temporary stage No. m = 4 is decided as a permanent stage No. 4. Subsequently, the program proceeds to step S26, in which the processing of the permanent stages is performed as similarly to the case of FIG. 4. That is, fuel injection is performed in a duration and amount read from a MAP according to stage computation. This fuel injection is performed normally during stages Nos. 4 to 11. This is due to the fact that a small-displacement motorcycle engine is operated at high speeds and it is therefore to start fuel injection at an early timing. Furthermore, in step S26, ignition is performed at a timing read from a MAP according to stage computation. This ignition is performed normally during stage Nos. 1 to 3. Thus, in the case of FIG. 6, at the time the crankshaft is rotated by two revolutions (720*) from starting of the engine, the fuel is completely exploded and normal operation can be started as similarly to the case of FIG. 4. While the partially untoothed gear 1 in this preferred embodiment has equally spaced nine teeth and an untoothed portion to generate nine pulses including an untoothed pulse by one rotation of the crankshaft, the number of teeth of the gear 1 may be set larger or smaller than 9 in the present invention. According to the present invention, the complete explosion can be made at least once during three revolutions of the crankshaft, and normal control can be reached by three revolutions of the crankshaft. Accordingly, it is possible to provide good startability not so inferior to the startability of a multicylinder engine. Furthermore, the fuel injection control device can be configured at a low cost, because it is not necessary to provide a cam pulser included in a multicylinder engine. In addition, fine control can be performed against rotation,fluctuations during one revolution of the crankshaft which fluctuations become larger with an increase in. number of cylinders, because the present invention adopts a system of generating a plurality of pulses per rotation of the crankshaft. [Explanation of Reference Numerals] 1: partially untoothed gear 2: pulse generator 3: ECU 4.: injector 5: spark plug 6: intake pressure sensor FIG. 1 3: ECU (ELECTRONIC CONTROL UNIT) 4: INJECTOR 5: SPARK PLUG 6: INTAKE PRESSURE SENSOR FIG. 2 A: STARTS 1: COUNT THE NUMBER OF PULSES FROM PARTIALLY UNTOOTHED GEAR (COUNT VALUE = n) S14: INJECT A GIVEN MINUTE AMOUNT OF FUEL S4: DETECT UNTOOTHED POSITION (= N) S5: DECIDE TEMPORARY STAGE NO. (= m) AND START TEMPORARY STAGES S18: IGNITION S19: HAVE Pbl AND Pb2 BEEN READ ? S28: DECIDE m = 4 AS PERMANENT STAGE NO. 13 S2 9: DECIDE m = 4 AS PERMANENT STAGE NO. 4 B: IN THE CASE OF FIG. 6 FIG. 3 S20: READ Pb (Pbl OR Pb2) S21: IGNITION C: IN THE CASE OF FIG. 4 OR 5 S12: HAVE Pbl AND Pb2 BEEN READ ? S13: FUEL INJECTION S17: READ Pb (Pbl OR Pb2) S23: DECIDE m = 13 AS PERMANENT STAGE NO. 13 S24: DECIDE m = 13 AS PERMANENT STAGE NO. 4 S2 5: FUEL INJECTION S2 6: INJECT FUEL IN A DURATION AND AMOUNT READ FROM MAP ACCORDING TO STAGE COMPUTATION, AND IGNITE AT A TIMING READ FROM MAP FIG. 4 A: (IN THE CASE OF STARTING ENGINE BEFORE COMPRESSION TOP DEAD CENTER) B: STROKES C: PARTIALLY UNTOOTHED PULSES D: (INTAKE PRESSURE) E: (FUEL INJECTION) F: (IGNITION) G: (STILL) H: EXPANSION I: EXHAUST J: INTAKE K: COMPRESSION L: COMPRESSION TDC M: EXHAUST/INTAKE TDC N: HOLD MINIMUM VALUE OF Pb 0: (START TEMPORARY STAGES) P: (START PERMANENT STAGES) Q: (START NORMAL OPERATION) R: (DURING STAGE NOS. 1 TO 3) S: (DURING STAGE NOS. 4 TO 11) FIG. 5 A: (IN THE CASE OF STARTING ENGINE BEFORE EXHAUST OR INTAKE TOP DEAD CENTER) B: STROKES C: PARTIALLY UNTOOTHED PULSES D: (INTAKE PRESSURE) E: (FUEL INJECTION) F: (IGNITION) G: (STILL) H: INTAKE I: COMPRESSION J: EXPANSION K: EXHAUST L: EXHAUST/INTAKE TDC M: COMPRESSION TDC N: (START TEMPORARY STAGES) 0: (START PERMANENT STAGES) P: (START NORMAL OPERATION) Q: (DURING STAGE NOS. 1 TO 3) R: (DURING STAGE NOS. 4 TO 11) FIG. 6 A: (IN THE CASE OF STARTING ENGINE IN THE MIDDLE OF EXPANSION STROKE AT A PISTON STOP POSITION CORRESPONDING TO AN UNTOOTHED POSITION) B: STROKES C: PARTIALLY UNTOOTHED PULSES D: (INTAKE PRESSURE) E: (FUEL INJECTION) F: (IGNITION) G: (STILL) H: EXPANSION I: EXHAUST J: INTAKE K: COMPRESSION L: EXHAUST/INTAKE TDC M: COMPRESSION TDC N: (START TEMPORARY STAGES) 0: (START PERMANENT STAGES) P: (START NORMAL OPERATION) Q: (DURING STAGE NOS. 1 TO 3) R: (DURING STAGE NOS. 4 TO 11) FIG. 9 A: (FOUR-CYLINDER ENGINE) B: ENGINE START C: CRANK ANGLE SENSOR OUTPUT D: TIMING SENSOR OUTPUT E: INJECTOR F: (SIMULTANEOUS INJECTION) We Claim 1. A fuel injection control device for a single-cylinder engine, comprising: pulse generating means for generating a given number of pulse signals including a plurality of equally spaced crank angle pulses and unequally spaced crank angle pulses per rotation of a crankshaft of said engine; injection control temporary stages allocated respectively to the durations of said pulse signals generated by said pulse generating means from the start Of cranking; intake pressure measuring means for measuring an intake pressure of said engine a plurality of times during two rotations of said crankshaft according to said injection control temporary stages; and injection control permanent stages shifted from said injection control temporary s€ages according to measured values of said intake pressure obtained by said intake pressure measuring means; Wherein initial fuel injection is performed within said given number of said pulse signals generated from the start of cranking per rotation of said crankshaft, and second and subsequent fuel injection and ignition are performed according to said injection control temporary stages and said injection control permanent stages. 2. A fuel injection control device for a single-cylinder engine as claimed in claim wherein said initial fuel injection is determined according to temperaltures of said engine. 3. A fuel injection control device for a single-cylinder engine as claimed in claim 1 or 2, wherein the timing of said initial fuel injection is set in a time period from the start of cranking to the time the number of said pulse signals generated becomes 1/2 of said given number of said pulse signals per rotation of said crankshaft. 4. A fuel injection control device for a single-cylinder engine as claimed ■" in claim l wherein when said crankshaft is rotated by one rotation, a start number of said injection control temporary stages is determined according to said unequally spaced crank angle pulses generated by said pulse generating means. 5. A fuel injection control device for a single-cylinder engine as claimed in claim 1, wherein a minimum value of said intake pressure of said engine is held until said intake pressure is measured. 6. A.fuel injection control device for a single-cylinder engine as claimed in claim 1, wherein said injection control permanent stages are made to eprrespond to strokes of said engine according to the magnitude of said measured values of said intake pressure 7. A fuel injection control device for a single-cylinder engine substantially as hereinbefore described with reference to the accompanying drawings. Dated this the 2nd day of March, 2000 [JAYANTA PAL] Qf Remfry & Sagar ATTORNEY FOR THE APPLICANTS]

Documents:

181-mum-2000-cancelled pages(8-6-2005).pdf

181-mum-2000-claims(granted)-(8-6-2005).doc

181-mum-2000-claims(granted)-(8-6-2005).pdf

181-mum-2000-correspondence(2-8-2007).pdf

181-mum-2000-correspondence(ipo)-(27-12-2007).pdf

181-mum-2000-drawing(8-6-2005).pdf

181-mum-2000-form 1(2-3-2000).pdf

181-mum-2000-form 1(27-7-2007).pdf

181-mum-2000-form 13(6-8-2007).pdf

181-mum-2000-form 19(15-4-2004).pdf

181-mum-2000-form 2(granted)-(8-6-2005).doc

181-mum-2000-form 2(granted)-(8-6-2005).pdf

181-mum-2000-form 3(23-2-2001).pdf

181-mum-2000-form 3(31-12-2004).pdf

181-mum-2000-form 5(2-3-2000).pdf

181-mum-2000-petition under rule 137(31-12-2004).pdf

181-mum-2000-petition under rule 138(31-12-2004).pdf

181-mum-2000-power of authority(11-8-2000).pdf

181-mum-2000-power of authority(31-12-2004).pdf

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